The presentation was about Maglev, an object server that provides automatically persisted objects without using an ORM or SQL. It allows objects to be transactional and multi-VM. The goals of Maglev include having no object to RDB mapping, no SQL queries, no save or update methods, separation of transactional code from model code, and no coupling between models and web frameworks. Examples showed using Maglev to develop investment portfolio applications with accounts, portfolios, and transactions just as objects without persistence concerns. Conclusions were that Maglev allows simpler, easier, and cheaper development just with objects.

1. Maglev
RubyConf Argentina 2012
Hernán Wilkinson
Twitter: @HernanWilkinson
Blog: objectmodels.blogspot.com
www.10pines.com
agile software development & services

3. What is the presentation about

4. Common WebApp Architecture

5. Common WebApp Architecture

6. Issues
Code vs. Data
Object vs. Data

7. Issues
Paradigm Mismatch
(Need a translator)

8. Issues
Design Errors
• Forced by the ORM
• Thinking in tables not in objects
• Difficult to create test objects – Mock
abuse!
• etc

9. Issues
More time to run!
• Tests run slow!
• Starting can take minutes due to
ActiveRecord!

10. Therefore…
More “Human” Time
Bigger Development Cost

11. Imagine…

12. Imagine…

14. Maglev
A…
– Transactional
– Automatically persisted
– Multi-VM
– NO RAM restricted
… Object Server

15. Maglev
• Two Modes:
– Transient mode (normal ruby)
– Persistent mode – The really interesting
one!
• Objects are naturally persistent
• On Commit, saves transitive closure from a root
object
• Transactional memory! (no deadlocks)

16. Example!
• Investment Accounts
– Balance:
• 10 pesos + 5 dollars
• 3000 bodens2012 + 600 futureDollarJan2013
• Portfolios
– Account composite
• Multiple Web Interface
– Sinatra (simple )
– Rails
• Using TDD!

19. Goals
1. No Object-To-RDB Mapping
– No Portfolio < ActiveRecord
– No id
2. No SQL SELECT…
3. No save! or update!
4. Separation of concern
– No transactional code mixed with model code
5. No Model to Web Framework coupling
6. Only Objects!
7. Development using TDD

20. Fulfilling Goals…
• No Object-To-RDB Mapping
– No Portfolio < ActiveRecord
– No id
• No SQL SELECT

21. Account Hierarchy

22. AccountTransaction Hierarchy

23. Measure Hierarchy

24. Fulfilling Goals…
• No Model to Web Framework coupling

25. PortfolioSystem and
PortfolioSinatraApplication

26. Fulfilling Goals…
• No save! or update!
• Separation of concern
– No transactional code mixed with model
code

27. Showing the home page

28. Adding an Account

29. FREEDOM!!!

30. Conclusions
• Just Objects!
• No ORM! No SQL! No ActiveRecord! 
• Tests run fast
• Developed really fast
• No need for mocks! – Bye bye FactoryGirl!
• We did not have to worry about
– Persistence
– Transaccionability
– Solved in one place

31. Conclusions
Simpler
Easier
Cheaper
…
Happier

32. Maglev
• Install with: rvm install maglev
• Ruby 1.8.7
• Rails:
– No scaffolding when using just objects
– Need to write generators
• Heroku??
• Licence
– Ruby code open source
– VM is not open source

33. Futurology
Relational Databases will fall in less than
10 years

34. • Diseño Avanzado de Softaware con Objetos I:
29 de Octubre
• Metaprogramación con Lenguajes de Objetos:
13 de Noviembre
• TDD:
19 de Noviembre
• Diseño Avanzado de Softaware con Objetos II:
4 de Diciembre
(50% de descuento si vinieron a esta conferencia!)
http://www.10pines.com/content/cursos-disponibles

35. Smalltalks 2012

36. Questions?

37. Muchas gracias!
info@10pines.com Argentina
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Buenos Aires
agile software development & services